This invention relates generally to in vivo sensors and more particularly to multiple sensors for use in arterial cannulae. Present in vivo sensors for medical applications are large and require insertion into major arteries. Recently, several miniature sensors using optical waveguides for the transmission of information have been developed for in vivo monitoring. Such miniature sensors have always been mounted in supporting enclosures such as catheter lumens, hypodermic needles, or other small tubes. Examples of miniature sensor systems include the catheter mounted K+ sensors described by D. M. Band and T. Treasure, J. Physiol. (London), 266, 12 (1977) and by M. S. Goorsky, J. S. Fowler, and R. C. Murray, Jr. in U.S. patent application Ser. No. 699,369 filed Feb. 7, 1986, and the needle-mounted fiber optic pH sensor described by D. R. Markle et al., A pH Measurement System For Use in Tissue & Blood, NIH, (personnal communication). Such sensor systems, mounted in needles or tubes, are not suited for use in radial arterial cannulae or for applications in other small arteries because they are either too large, too stiff, or cannot accommodate multiple sensors and still remain small and flexible. Radial arterial cannulae typically have a diameter of 900 .mu.m or less, thus limiting the size of the inserted sensor. Advantages for using radial or other small arteries for in vivo sensor insertion include: easier accessibility, less trauma to the patient, and lower risk of serious side effects or damage to major arteries. Therefore, it is an object of the present invention to provide a multiple sensor bundle which can be readily inserted into, and removed from, a radial or other small artery cannula for use in continuous in vivo patient monitoring.
Additional objects, advantages, and novel features of the invention will be set forth in part in the description which follows and in part will become apparent to those skilled in the art upon examination of the following or may be learned by practice of the invention.